1. Field of the Invention
The present invention relates to a sealing device.
2. Description of the Relevant Art
Computers or electrical devices are sometimes deployed in surroundings exposed to environmental elements. For example, telephone interface devices may be located on telephone poles, in boxes at a roadside, or under a body of water. Such devices are housed inside sealed enclosures to protect sensitive electrical equipment from exposure to contaminants, such as water, insects and dust.
Often many incoming and outgoing cables, such as electrical cables and fiber optic cables, are connected to the sensitive electrical equipment inside the sealed enclosure and communicate to the world outside the enclosure. Therefore, some arrangement must be provided around the cables to allow the incoming and outgoing cables to enter and exit the enclosure, without violating the sealed integrity of the enclosure.
FIG. 1 illustrates a cable sealing arrangement in accordance with the background art. FIG. 1 is a cross sectional view of an enclosure 12 having a first side wall 1, a second side wall 2, and a upper surface 3. Cable ports 4 are provided on the upper surface 3.
Each cable port 4 includes a continuous cylindrical wall 5 extending upward and away from the upper surface 3. The continuous cylindrical wall 5 is closed by a top wall 6 at an upper end, and the continuous cylindrical wall 5 opens into the interior of the enclosure 12 at a lower end.
The enclosure 12 is initially formed with a plurality of cable ports 4, such as ten.
Each of the cable ports 4 is initially closed by a respective top wall 6. Depending upon the circuitry and functions of the electronics encased within the enclosure 12, a technician determines how many cables, and what gauge cables, are needed to enter/exit the enclosure 12. FIG. 1 illustrates two cables entering/exiting the enclosure. A first cable 7 has a relatively large gauge. A second cable 8 has a relatively small gauge.
Next, cable ports 4, having a continuous cylindrical wall 5 with a diameter appropriate to the gauge of the first and second cables 7, 8, are opened. A cable port 4 is opened by removing its top wall 6 from the continuous cylindrical wall 5. In this example, two top walls 6 have been removed. The top walls 6 are typically removed using a hacksaw.
In the case of the first cable 7, the technician installs a heat shrink wrap assembly onto an end of the first cable 7, and slides the heat shrink wrap assembly up onto the first cable 7. The heat shrink wrap assembly includes a plastic membrane 10 and a melting epoxy 11, within the plastic membrane 10. The technician passes the first cable 7 through the appropriate opened cable port 4. Then, the plastic membrane 10 is slid onto the outer surface of the continuous cylindrical wall 5. Lastly, the technician applies heat to the plastic membrane 10, which causes the melting epoxy 11 to seal the cable port 4.
The cable port 4, according to the background art, suffers drawbacks. Cutting off the top wall 6 takes time and thus delays the assembly process. Also, the sawing off of the top wall 6 can result in sharp burs along the edges of the continuous cylindrical wall 5. Removal of the burs, such as by filing, further delays the assembly time. Leaving the burs can result in damage to the insulation layer, shielding layer and/or conductors within the cables 7, 8.
A further drawback results if the technician cuts the continuous cylindrical wall 5 at a slant. A slanted cut reduces the surface area of the continuous cylindrical wall 5 available for bonding to the melting epoxy 11, and thus reduces the integrity of the seal formed at the cable port 4. An even further drawback is that the upper surface 3 of the enclosure must be initially formed with a plurality of differently sized cable ports 4, in order to be able to accommodate differing gauges of cables.
Accordingly, it is an object of the invention to provide a system for sealing cables, which overcomes one or more of the drawbacks associated with the background art.
It is a further object of the invention to provide a cable sealing arrangement, which reduces the assembly time required to seal cables entering/exiting the enclosure.
It is an even further object of the invention to provide a cable sealing arrangement, with an improved sealing integrity.
It is an even further object of the invention to provide a uniform cable port design, which can accommodate cables of various gauges.
These and other objects of the invention are accomplished by a sealing device and a method of sealing a cylindrical object, such as an electrical or fiber optic cable, where the sealing device includes a base with a first end, a second open end, and an inner wall formed inside the base and connecting the first end to the second open end. The sealing device also includes a cap having one end which is open and another end which is attached to the first end of the base. The one end of the cap includes a first cylindrical recess of a first diameter extending toward the base. In a first embodiment, a hole is drilled through the cap using the first cylindrical recess as a guide. A cable is passed through the hole and a heat shrink wrap assembly is used to seal the cable. In a second embodiment, the cap is removed from the base along a frangible connection. A threaded fastener with a first hole and a gasket with a second hole are provided. A cable is passed through the first and second holes, and the threaded fastener is screw onto the base to seal the cable.
Other objects and further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.